Color fast synthetic textile fibers from vinyl lactam polymer-containing acrylonitrile polymers



Jan. 26, 1960 A. s. MESSER I 2,922,692

COLOR FAST SYNTHETIC TEXTILE FIBERS FROM VINYL LACTAM POLYMER-CONTAININGACRYLONITRILE POLYMERS Filed Dec. 28, 1956 IN VEN TOR.

fl/ber/ I5, Messer BY HTTORNEKS United COLOR FAST SYNTHETIC TEXTILEFIBERS FROM VINYL LACTAM POLYMER-CONTAINING AC- RYLONITRILE POLYMERSApplication December 28, 1956, Serial No. 631,255

8 Claims. (Cl. 8-74) This invention relates to the provision of colorfast vinyl lactam polymer-containing acrylonitrile polymer synthetictextile fibers and the like that have been dyed with certain types ofdyestuffs and rendered stable to the deleterious efiects of light whilein a colored'condition.

Certain vinyl lactam polymers, particularly polyvinyl pyrrolidone, areexceptionally well adapted for employment as dye-assisting adjuvants inshaped acrylonitrile polymer articles, particularly polyacrylonitrilefibers and the like, including filaments, yarns, films and relatedstructures. For convenience, the various shaped articles that may befabricated from synthetic, linear, fiber-forming acrylonitrile polymerswill hereinafter be illustrated with fibers that are manufactured withsuch compositions. A great general improvement in dyeability with almostall of the available dyestuffs and coloring agents may be secured whenvinyl lactam polymers, particularly polyvinylpyrrolidone, areincorporated in acrylonitrile polymer synthetic textile fibers. Despitethis, certain difficulties may also attend such practice when it isdesired to impart coloration to the fibers by means of many direct, acid(including acidpremetaIliZed) and chrome types of dyestuffs.

By way of illustration, when vinyl lactam polymercontainingacrylonitrile polymer fibers are dyed with many of the direct, acid andchrome dyestuifs, the colored synthetic fiber product has a tendency tobe unstable upon exposure to light so that they may definitely andnoticeably fade in a most undesirable manner. This is notwithstandingthe fact that good color yields and intense depths of shade may beinitially achieved with such dyestuffs on vinyl lactampolymer-containing acrylonitrile polymer fibers and that such varietiesof dyestuffs are normally quite color stable on exposure to light whenthey have been applied to thevarieties of fibers for which they wereoriginally designed and intended to be utilized upon.

This failure to be light fast when colored with direct, acid and chromedyestuffs, as is apparent, tends to limit the otherwise generally utilecharacteristics of vinyl lactam polymer-containing acrylonitrile polymersynthetic fibers from employment as textile materials that are intendedto be colored by such dyestuffs to avoid the obviously undesirableconsequences that might accrue. It would be advantageous to overcomethis deficiency in such fibers.

Therefore, it is principally the objective of the present invention toprovide light stabilized vinyl lactam polymercontaining acrylic fibersand the like dyed with either direct, acid or chrome dyestulfs thatwould be substantially free from tendencies to fade upon exposure tolight, including ultra violet light, in the course of their useful livesas textile materials. Other objectives and advantages ancillary. to theprincipal objective that may be realized by practice of the presentinvention are manifest in the ensuing description and specification.

In accordance with the present invention, Vinyl lactampolymer-containing acrylic fibers that have been dyed with a dyestuffselected from the group consisting of Patent M 2,922,692 Patented Jan.26, 1960 direct, acid and chrome dyestuffs may be rendered stable tolight and resistant to fading from the initially obtained coloration bya treatment which comprises subjecting them after they have been dyed toan aqueous solution of cuprous ions, preferably obtained from cupricions(as from copper sulfate) that have been converted to cuprous ions by theaction of hydroxyl amine sulfate or an equivalent reducing agent forcupric ions. Bene, ficially, the treatment is conducted immediatelysubse quent to the dyeing operation. Advantageously, the aqueoussolution of copper ions that is employed for the treatment contains aquantity of the ions that is equivalent to that which is obtained in anaqueous solution of copper sulfatecoritaining from about 0.5 to 8percent by weight, based on the weight of the fibers, of dissolved salt,and, more advantageously, from. about 0.5 to 5 percent on the weight ofthe fibers of the dissolved salt in treating baths wherein the weightratio of bath-.tofiber may respectively range from about 5:1 to about100:1. Thus, the treating solution advantageously may be made up by theadditionof from about 0.005 to 1.6 and, more advantageously, from about0.005 to 1.0 gram of copper sulfate to each 100 grams of treatingsolution being prepared. Of course, when other copper ion-providingsalts are utilized, their gravimetric proportions will vary from theindicated values for copper sulfate in accordance 'with the copperequivalent weight of the particular copper salt that is employed. Thesame ranges of weight concentrations in solution may advantageously beemployed for a hydroxyl amine sulfate reducing agent and, in a similarmanner, when other reducing agents for cupric ions are utilized,proportions of them that are equivalent in reducing activity to suchconcentrations of hydroxyl amine sulfate are usually advan tageous. Inmany instances it may be suitable'to employ an approximately equalweight perecnt'age of copper sulfate and hydroxyl amine sulfate in'thetreating solution. Frequently, vinyl lactam polymer-containingacrylonitrile; polymer synthetic textile fibers that have been, imbued.with light shades of coloration from direct, acid or chrome .dyes'tutfsmay be suitably stabilized against light fading when: the concentrationof reagents in the treating solution is at ortowards the lower extremityof the indicated ranges. Darkerzh-nesmay' often be better stabilizedwith more concentrated'treating solutions.

The treatment may beconducted for periods of at least one-half. hour atvtemperatures fromna'bout. 70 C. to the boil.

may be-realized in comparison with untreated fibers 'of the sametypethat have been dyed with the same varieties of dyestuffs. A dyed vinyllactam polymer-containingacrylonitrile polymer synthetic textile fiberthatis st'abilized against fading upon exposure to light by treatment inaccordance withv the. present. invention is schematically represented,in an exaggerated perspective, in the accompanying-drawing. Y

Although copper sulfate" (CuSO;,)- is," as has been i n dicated, apreferred source of'copper ions, other copper salts may also be utilizedfor'such purpose including cop per acetate, copper chlorideandthelike.Likewise, such reducing agentsizas sodium sulfoxylate formaldehyde, me-

O ftentimes, however, ebullient tempera-- tures, or temperatures of atleast. about C. are better 3 tallic elemental copper, mixtures of sodiumbisulfite with glyoxal and the like may also be employed in the practiceof the invention, despite the great desirability of hydroxyl aminesulfate for such application. No special dyeing technique or procedurefor the direct, acid or chrome dyestuffs is necessary when it isintended to stabilize the colored vinyl lactam polymer-containingacrylonitrile polymer fiber by practice of the invention. The usual andconventional techniques that are commonly employed in the art may beused on the fibers prior to the stabilizing treatment.

Advantageously, the vinyl lactam polymer containing V mg of Benzo AzurmeGA (Cl. 502), a direct dye, by

acrylonitrile polymer fiber that may be dyed with direct, acid or chromedyestuffs and aftertreated for light fastness according to the presentinvention is derived from a fibervinyl caprolactam. When vinyl lactamcopolymers are utilized, it is frequently desirable to employ those thatcontain at least about 60 or even 80 percent by weight of the vinyllactam monomer polymerized inthe copolymer molecule.

Generally, it is beneficial for a vinyl lactam polymercontainingacrylonitrile polymer synthetic textile fiber to contain up to 20percent by weight of a dye-receptive vinyl lactam polymer in intimatephysical incorporation in the acrylonitrile polymer. It may frequentlybe of greatest advantage when between about 6 and 12 percent by weightof the vinyl lactam polymer, particularly polyvinylpyrrolidone, isincorporated in the acrylonitrile polymer, particularlypolyacrylonitrile, based on the dry weight of the associated polymers.While vinyl lactam polymep containing acrylonitrile polymer synthetictextile fibers of the indicated variety may be literally referred to asacrylic fibers for purposes of broad generic classification, it isgenerally preferred, when brevity is a requirement, to characterize themas being nitrile alloy fibers in order to clearly distinguish them fromthe conventional prototype acrylic fibers that are known to the art.

. Various techniques and procedures may be invoked for providing a vinyllactam polymer-containing acrylonitrile polymer fiber of the indicatedvariety. For example, the vinyl lactam polymer may be uniformlyincorporated in the desired quantity in a fiber-forming acrylonitrilepolymer composition prior to spinning it into fibers in order to preparethe desired dye-receptive synthetic fiber product. Advanta'geously,however, the vinyl lactam polymercontaining acrylonitrile polymer fibermay be a wet spun product in which the vinyl lactam polymer isintimately incorporated by impregnation of the dye-assisting adiuvantfrom an aqueous solution thereof while the acrylonitrile polymer in thefiber is in a swollen or gel condition. Thus, a fiber-forming polymer ofacrylonitrile such as polyacrylonitrile may be prepared as a spinningsolu tion by dissolving it in asuitable solvent, such as an aqueous 60percent by weight zinc chloride solution, and extruded in solution intoa coagulating bath therefor to initially form an aquagel filamentarystructure in which the vinyl lactam polymer may conveniently beincorporated by subjecting the aquagel structure to treatment with animpregnatingrsolution ofthe dye-assisting adjuvant. Such animpregnatingtreatment may often be suitably performed by passing theaquage'lthrough an aqueous treatingbath of dissolved vinyl lactampolymer prior to drying the aquagel to a dehydrated condition.

' aeaaeez The invention will be further illustrated in and by thefollowing examples wherein,-unless otherwise indicated, all parts andpercentages are to be taken by weight, In each of the examples the vinyllactam polymer-containing acrylic fiber consisted ofS-runpolyacrylonitrile yarn in which there was intimately incorporated aboutpercent by weight, on the dry weight of the fiber, ofpolyvinylpyrrolidone as a dye-assisting adjuvant.

Example I About 5 grams of scoured polyvinylpyrrolidone-containingpolyacrylonitrile fiber was given a 2 percent dyeinitially setting thedyebath at 50 C., immersing the fiber in the dyebath, bringing thedyebath to the boil over a minute period, adding 30 percent, on theweight of the fiber, of sodium chloride to the dyebath over a 15 minuteperiod, and continuing the dyeing at the boil for a 2 hour period. Theresulting fiber, which was deep and level dyed, was then given a coldrinse with water before being immersed in about 150 milliliters of atreating bath consisting ofJS percent of copper sulfate and 2.5 percentof I hydroxyl amine sulfate, both based on the weight of the fiber.After placing the dyed fiber in the treating solution, the temperaturewas rapidly raised to about 95 C. and the dyebath was synthermallymaintained for a 30 minute period. The dyed and treated fiber was thenremoved from the treating solution, rinsed thoroughly with cold waterand dried. It had excellent light stability and was extremely color-fastupon exposure to light. For example, when the dyed and treated fiber wastested under exposure to ultra violet light in a standard AtlasFadeometer, a noticeable color fade did not occur until after expirationof a 20 hour period. In comparison, a similarly dyed but untreated fiberof the same type faded after 'only 5 hours of exposure in theFadeometer."

I Example II w v I Example III In substantially identical repetitions ofthe procedures of Example I with different dyestufis and slightvariations in the concentrations of the reagents in the stabilizingtreatment solutions, the color fastness of a number of dyed vinyl lactampolymer-containing acrylonitrile polymer synthetictextile fiber sampleswas enhanced to a degree commensurate with that illustrated in thepreceding examples. The following tabulation lists and identifies someof the dyestuffsemployed for the color stabilized acrylic fibers thatwere prepared. It also includes the nature of the, dyeing with each dyeand the Weight concentrations,

- all based on the weight of the fiber, of the copper sulfate CS) andhydroxyl amine sulfate (HAS) reagents that were m the particulartreatnig solutions employed for stabrlizmg the dyed fibers.

Acid dyestuffs:

Direct dyes:

2 percent Cuprofix Rubine BL-Pr. 491; 4 percent CS+4 percent HAS 2percent Diazo Fast Blue 2RWC.I. 317; 4 percent CS+4 percent HAS 1percent Direct Brilliant Sky Blue 63 ex. cone.-

C.I. 518; 4 percent CS+4 percent HAS 5 percent Direct Black E ex.conc.C;I. 581; 5 percent CS+5 percent HAS 2 percent Diamine BrownMBA-C.I. 420; 4 percent CS+4 percent HAS Chrome dyestuffs:

1.4 percent Anthranol Chrome Red GL conc.Pr.

135; 3 percent CS+3 percent HAS 2 percent Omega Chrome Red BC.I. 652; 3percent CS+3 percent HAS 2 percent Chrome Fast Orange 3 RL A CFPr. 247;

3 percent CS+3 percent HAS 2 percent Chrome Blue 2R-Pr. 7; 2 percentCS+2 percent HAS 2 percent Alizarine Light Grey ZBLW-Pr. 206; 2

percent CS+2 percent HAS Those skilled in the art will readily recognizeand appreciate that the treatment of the present invention difiers inboth substance and essence from certain diverse copper ion treatmentsthat are known in connection with other of the conventional prototypeacrylic and other synthetic fibers to either directly assist inchemically attaching a dyestutf that otherwise would not becomeassociated with the polymer in the fiber or for causing a metallizingefiect of an already attached dyestufi in the fiber. As has beenindicated and as it is intended to be construed herein and in thehereto-appended claims, the term acid dyestuffs is meant to comprehendand to include within its generic purview the types of acid dyestuffsthat are sometimes referred to and characterized as beingacid-premetallized dyes.

What is claimed is:

1. Process of rendering color-fast a dyed synthetic textile fiber thatis comprised of (a) a fiber of an intimate alloy composition of (1) afiber-forming acrylonitrile polymer that contains in the polymermolecule about 85 Weight percent of acrylonitrile and (2) a minorproportion of up to about 20 Weight percent, based on the weight of thedry fiber, of a vinyl lactam polymer, said fiber being colored with (b)a dyestutf attached thereto selected from the group of dyestuffsconsisting of direct, acid and chrome types of dyes, which processcomprises treating said dyed fiber, for at least about half an hour at atemperature of from about 70 C. to the boil with an aqueous treatingsolution at a bath-to-fiber weight ratio between about 5:1 and 100:1,respectively, said treating solution containing (A) an amount of cupriccopper ion equivalent to that which is obtained with between about 0.5and 8 percent by weight, based on the weight of the fiber, of coppersulfate (CuSO and (B) an amount of a reducing agent for cupric copperions that is equivalent in activity to an aqueous solution of from 0.5to 8 percent by weight, based on the weight of the fiber, of hydroxylamine sulfate to render fast-to-light the color in said dyed fiber.

2. As an article of manufacture, a colored and color fast-to-lightsynthetic textile fiber obtained as the product of the process of claim1.

3. Process of manufacturing a color-fast synthetic textile fiber that iscomprised of an intimate alloy composition of (1) a fiber-formingacrylonitrile polymer that contains in the polymer molecule at leastabout 85 weight percent of acrylonitrile and (2) a minor proportion ofup to about 20 weight percent, based on the weight of the dry fiber, ofa vinyl lactam polymer, which process comprises first dyeing saidsynthetic textile fiber with a dyestuff selected from the groupconsisting of direct, acid and chrome types of dyes and subsequentlytreating said dyed fiber, for at least about half an hour at atemperature be tween about C. and the boil, with an aqueous treatingsolution at a bath-to-fiber weight ratio between about 5:1 and 100:1,respectively, said treating solution containing (A) between about 0.5and 8 percent by weight of copper sulfate (CuSO and (B) between about0.5 and 8 percent by weight of hydroxyl amine sulfate, both based on theweight of the fiber, to render fast-to-lightthe color in said dyedfiber.

4. The process of claim 3, the after-dyeing treatment being conducted ata temperature between about C. and the boil.

5. The process of claim 3, wherein the after-dyeing treatment isconducted in an aqueous treating solution containing separate amounts ofbetween about 0.5 and 5 percent by weight ofthe copper sulfate and thehydroxyl amine sulfate, both based on the Weight of the fiber.

6. The process of claim 3, wherein about equal weights of copper sulfateand hydroxyl amine sulfate are contained in the aqueous treatingsolution employed after said dyeing.

7. The process of claim 3, wherein the treating bath-tofiber weightratio that is utilized in the after-dyeing treatment is in theneighborhood of 30: 1.

8. The process of claim 3, wherein said synthetic textile fiber iscomprised of polyacrylonitrile in which there is intimately incorporatedan amount between about 6 and 12 percent by weight, based on the weightof dry fiber, of polyvinylpyrrolidone as a dye-assisting adjuvant.

References Cited in the file of this patent UNITED STATES PATENTS2,643,990 Han June 30, 1953 2,790,783 Coover Apr. 30, 1957 FOREIGNPATENTS 678,106 Great Britain Aug. 27, 1952 696,984 Great Britain Sept.9, 1953 OTHER REFERENCES Am. Dyestutf Reporter for May 9, 1955, p. P323,art. by W. H. Hindle.

Blaker: Am. Dyest. Rep., January 21, 1952, pp. 39-43.

Br. Rayon and Silk Jour., August 1953, p. 54.

1. PROCESS OF RENDERING COLOR-FAST A DYED SYNTHETIC TEXTILE FIBER THATIS COMPRISED OF (A) A FIBER OF AN INTIMATE ALLOY COMPOSITION OF (1) AFIBER-FORMING ACRYLONITRILE POLYMER THAT CONTAINS IN THE POLYMERMOLECULE ABOUT 85 WEIGHT PERCENT OF ACRYLONITRILE AND (2) A MINORPROPORTION OF UP TO ABOUT 20 WEIGHT PERCENT, BASED ON THE WEIGHT OF THEDRY FIBER, OF A VINYL LACTAM POLYMER, SAID FIBER BEING COLORED WITH (B)A DYESTUFF ATTACHED THERETO SELECTED FROM THE GROUP OF DYESTUFFSCONSISTING OF DIRECT, ACID AND CHROME TYPES OF DYES, WHICH PROCESSCOMPRISES TREATING SAID DYED FIBER, FOR AT LEAST ABOUT HALF AN HOUR AT ATEMPERATURE OF FROM ABOUT 70*C. TO THE BOIL WITH AN AQUEOUS TREATINGSOLUTION AT A BATH-TO-FIBER WEIGHT RATIO BETWEEN ABOUT 5:1 AND 100:1,RESPECTIVELY, SAID TREATING SOLUTION CONTAINING (A) AN AMOUNT OF CUPRICCOPPER ION EQUIVALENT TO THAT WHICH IS OBTAINED WITH BETWEEN ABOUT 0.5AND 8 PERCENT BY WEIGHT, BASED ON THE WEIGHT OF THE FIBER, OF COPPERSULFATE (CUSO4), AND (B) AN AMOUNT OF A REDUCING AGENT FOR CUPRIC COPPERIONS THAT IS EQUIVALENT IN ACTIVITY TO AN AQUEOUS SOLUTION OF FROM 0.5TO 8 PERCENT BY WEIGHT, BASED ON THE WEIGHT OF THE FIBER, OF HYDROXYLAMINE SULFATE TO RENDER FAST-TO-LIGHT THE COLOR IN SAID DYED FIBER.